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<h2><span class="refentrytitle">Struct template hash</span></h2>
<p>boost::hash — A <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1836.pdf" target="_top">TR1</a> compliant hash function object.</p>
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<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2>
<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: &lt;<a class="link" href="../hash/reference.html#header.boost.container_hash.hash_hpp" title="Header &lt;boost/container_hash/hash.hpp&gt;">boost/container_hash/hash.hpp</a>&gt;

</span><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> T<span class="special">&gt;</span> 
<span class="keyword">struct</span> <a class="link" href="hash.html" title="Struct template hash">hash</a> <span class="special">:</span> <span class="keyword">public</span> std::unary_function&lt;T, std::size_t&gt; <span class="special">{</span>
  <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <a class="link" href="hash.html#id-1_3_11_11_2_2_1_4-bb"><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span></a><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
<span class="special">}</span><span class="special">;</span></pre></div>
<div class="refsect1">
<a name="id-1.3.11.11.3.6.4"></a><h2>Description</h2>
<pre class="literallayout"><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <a name="id-1_3_11_11_2_2_1_4-bb"></a><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span> val<span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>
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<td><p><span class="term">Returns:</span></p></td>
<td>
<p>
            </p>
<pre class="programlisting"><a class="link" href="../hash/reference.html#boost.hash_va_1_3_11_11_2_2_27_1">hash_value</a><span class="special">(</span><span class="identifier">val</span><span class="special">)</span></pre>
<p>
          </p>
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<td><p><span class="term">Notes:</span></p></td>
<td>
<p>
              The call to <code class="computeroutput"><a class="link" href="../hash/reference.html#boost.hash_va_1_3_11_11_2_2_27_1">hash_value</a></code>
              is unqualified, so that custom overloads can be
              found via argument dependent lookup.
            </p>
<p>
              This is not defined when the macro <code class="computeroutput">BOOST_HASH_NO_EXTENSIONS</code>
              is defined. The specializations are still defined, so only the specializations
              required by TR1 are defined.
            </p>
<p>
              Forward declared in
              <code class="computeroutput">&lt;boost/container_hash/hash_fwd.hpp&gt;</code>
            </p>
<p>
              This hash function is not intended for general use, and isn't
              guaranteed to be equal during separate runs of a program - so
              please don't use it for any persistent storage or communication.
            </p>
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<td><p><span class="term">Throws:</span></p></td>
<td><p>
            Only throws if
            <code class="computeroutput"><a class="link" href="../hash/reference.html#boost.hash_va_1_3_11_11_2_2_27_1">hash_value</a>(T)</code> throws.
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<td align="right"><div class="copyright-footer">Copyright © 2005-2008 Daniel
      James<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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